Method of manufacturing connection plugs



July 30, 1929. B. K. FORD l 1,722,739

METHOD OF MANUFACTURING vCONNECTION PLUGS Filed July 27, 1927 PatentedJuly 30, @29

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This invention relates to method of manufacturing connecting plugs, andmore paring plugs which are designed to engage jack contactsattached toother conductors and which jaclr contacts may be fiXedly positioned. frplurality of individually insulated conductors of this type assembledunder commony sheath to constitute a' flexible strand termed a cord isfrequently used in telephone exchanges for interconnecting elec-Y tricalcircuits of 'telephoneswitchboards; ln such cases the connectingplugattached to the cord is usuallyprovided with contacting portionswhich are insulated from each other7 individually connected with theconductors of the cord and designed to engage cooperating contactingportions or springs. Vof a jack terminal secured in the telephoneswitchboard. Due to the continual insertion and withdrawal by aswitchboard operator of the plugin and from thejacls yof the switchboardthe plug is subjected to considerable wear7 stress and strain and theirreplacement may therefore be quite frequent.

The primary objectof this invention is the provision ofa methodofmanufacturing a connecting plug for electrical conductors whereby itmay be quickly and Vsecurely as sembled inv'an expeditious, efficientand'economical manner. Y

In accordance with ject the present invention Vcontemplates a method ofmanufacturing a connecting plug,

consisting of a'plurality of contacting eie-L ments which are insulatedfrom eachother and which are provided with conducting portionspositioned in 'the body portion of the plug to receive thevends of theIelectrical conductors and enclosed by an insulating sleeve. Integralwith the body portion is aihollow projecting portion through which, andinsulated therlfrom, the`r conducting portions of the contactingelements extend. The conducting portion of onel of the contactingelements which specifically constitutes the tip of the connecting plugassembly, consists of a steel wire, such as music wire, provided at oneend with a series of circularly arranged the aforementioned ob-v isev.-semi no. acaeea.

depressions in which the metal of the tip contion will more fullyappear' from the acompanying detailed description takenA in connectionwitn theaccompanying drawing which illustrates one embodiment thereofyinwhich VFig. lispan elevation of an electrical conf necting plugmanufactured vin accordance with the limproved method shownr attachedtoacord; y

2 is a section onthe line 2 12 thereof looking in the directionindicated by the arrows; je ,l 4

Fig 3 is a perspective viewv of the center p1n; f

Fig. l is an enlarged section on the line i-l of Fig. 3 looking in thedirection indicated by the arrows; Y j

Figs. 5 and 6 are enlarged perspective views of the tipcontact anddead.collar;A

Fig. 7 Ais a perspective view oflan insulating member, and f Fig. 8 isan enlarged section on. the linev 8-8 o'fFig. 2 looking in the directionindicated by the arrows. 'l f rThis invention is particularly applicableto the manufacture of a connecting plug struc-l ture for telephone cordsand in the embodi-v nient illustrated in .tlie drawings is of the' threeconductor-typeythat is, it provides for.

the extension of suitable contacts Vof the ack. I

' (not shown) ofthreeconductors. 'lhe plug consists of al tubular,bodyportion 10 and aV projecting sleeve portion ll, ofless -diameterthanvthe portion'l()7 which is adapted to be inserted in a jack terminalto make electricalV Y contact with certain contact springs thereof.

The body portion l0 is-cut away intermediate its ends as shown at l2 toform a web portion ias for the purpose of affording access to its interior at pointswhere conductors of the cord are tobe' connected tocertain terminals to be referred to hereinafter. Carried within the fbore of the sleeve portion l1 is an insulating sleeve 13, a conductingsleeve 14, an insulating sleeve and a 'center pin 1,6k mounted onewithin the other in the sequence named.1 The kinsulating,sleeve 13 hasformed on the outer -end thereof` (Fig. 2) a flangedportion 17,

while the inner en-d thereof extends along the bore ofthe sleeve portion11`and terminates adjacent the inner shoulder of the bore of the bodyportion 10. The outer end of the conducting' sleeve 14 is formed with anenlarged ring portionv 18 which is'insulated from thev outer end ofvthersleeve portion 11 by the iianged portion 17 of the insulating sleevev13,

'while the inner end of the sleeve 14 is Closed `forthe purpose ofproviding 'a supporting portion for a screw 2O for securing one of the lportion thereof.

` Mounted upon the insulating sleeve 15 isa dead collar 22`of conductingmaterial, which is insulated onr its inner end from the adjacent endsurface ofthe portion 18 of the sleeve 14 by any insulating washer 23and on its outer end by a similar vwasher 23 from the inner end surfaceof a tip vmember 24, the member is .fitted tight on the center pin 16 sothat it must lbe slightly forced wlienassembl-ed thereon.

The flat end faces of the dead collar 22 are lznurled as shown at 25(Fig. 6) also the inner Y flat end face vof the tip member 24 is knurledas shown at 26 (Fig. 5). The purpose of the lniurling of these faces ofthe 'collar 22 and tip Y member 24 is'to prevent the rotation of thewashers r23 and the' collar 22 relative to each otheror to otlierpartsof the plug during a subsequent profiling or finishingoperation to bereferred to hereinafter. It will be ap'- parent in the completed plug aswell as during the operation just referred to wherein the various partsaxially vdisposed upon the center pin 16 are maintained undercompression one against the other, that the knurled metal end faces ofthe collar 22 andtip member 24 will y be'pressed into the adjacent endfaces of the comparatively soft material composing the washers 23, thussecurely locking the'washers and collar 22 from rotation.

Referring to Figs. 2, 3 and 4, particularly F ig. 4, it will beobservedthat the outer end (Figs. 2 and 3) of the center pin 16, whichis madev of a material similar to music wire for the purpose ofproviding a maximum stiffness or rigidity to the plug, is provided withfour equally `spaced shallow notches 29, two of the notches appearing inFigs. 2 and v3. In assembling the plug, the tip member 24 is staked onthe center pin 16 in such la manner that the peripheral surface of thebore thereof is lodged or forced down into the notches r29 to completelyfill them with the metal composing the tip and thereby lirmly securingthe latter member from relative vvmovement in all directions on the pin16. Between the peripheral surface of the bore of the body portion10'and the peripheral surface of that portion of the sleeve' 14ext-ending thereinto is lan insulating sleeve 27 which is an extensionof the insulating sleeve 13, the two sleeves overlapping as shown at 28.

Electrically weld-ed to tliefrigh't end of thev center pin 16, before`the assemblage lof the plug, is aterminal plate 30 2) provided with aright angle shoulder 31, which is rounded at its upper end sur-face asviewed in Figs. 2, 3 and 8 to conform to the'curv'a'- relay electricalpath between the body portion 10 and the shoulder 31. One end oftheshell' v32 engages a'shoulder33 ff'ormed'on the body portion 10 adjacentits1 inner end, the opposite end extending toa point adjacent Aashoulder 34 provided on the body portion 1Q in forming the sleeveportion 11 thereof, and is iiXed to the body portion 10 by a screw 35(Fig. 1).

The outer vertical faceof the. shoulder 31 of the plate 3 0 as well asthe lower face of the latter is yspaced from thesurfaces of the bodyportion 10 produced in the forming of the web portion 12 thereof by aninsulating mem- 'ber 36 (Fig. 7) provided with a rightangle arm 37, thearm serving to insulate. the inner end surface of the conducting sleeve14 from the plate 30, the sleeve 14 being cut away to` 1 'conform to theweb portion 12 of the body 10, as will readily be understood.-k VTheniember 36 is provided with a suitable slot 38 `for that portionof thecenterl pin V16 which is welded to the plate 30. A screw 39 similar tothe screw 2O threaded into theV closed end of the conducting sleeve 14is threaded into.'

the plate 30 for securing another one of the three conductors to thecenter pin 16.

Another of the. three conductors constitut-i ing the cord' 21 ismaintained in electrical contact with the peripheral wall of athreaded-portion 40 of thebore of the body portion 10 at its inner endby'turning back the' bared conductor which is lirmly held in' elec#trical contact with thethreaded portion by the cord which is threadedtl'iereinto. The

screws 39 and 21 'each secure onelofthec'cnlio ductors to the center pin16 to which is staked the tip member24'and the conductingsleeve curedanother cord in the manner hereinbefore referred to. The tip contact,the ring portion and the sleeve portion of the body, respectively, beingincluded in what are generally termed the tipff ring. and sleevecircuits in telephone exchange circuits.

During the iinal assemblage of the connecting plug herein described thetip member 24:, dead collar 22, insulating washers 23 at either end ofthe latter, conducting sleeve 14 and insulating sleeve 13 are maintainedunder pressure against the left end of the sleeve portion 11 of the plugbody 10 and simultaneously therewith the shoulder v31 of the plate 30,which is welded to the center pin 16 is pressed against the arm 37 ofthe insulating member 36 in turn backed by a vere ltical surface (Fig.2) of the body portion 10 formed at one end of the cut away or webportion 12 thereof. This pressure brings the various parts closetogether and serves to press the knurled metal end faces of the collar22 and tip member 24 into the adjacent faces of the washers 28, ashereinbefore described, thusA securelyV locking these partsV together.Vfhile the aforementioned parts are under compression suitable meansis'employed to stake the tip member 2a ontothe center pin 16, asliereinbefore described, thus forcing the metal of the tip member intothe notches 29 and securely locking the parts while under compression tothe body portion 10. After completion of the assemblage the sleeveportion 11 of the body portion 10, together Vwith the portion of theplug extending from the left end thereof 2), is polished oi' pro-l filedto provide a desired contour for insertion in the jacks of theswitchboard. The center pin 16 with the terminal plate 80,-securedthereto is mounted within thebody 10 by inserting it through the openingformed in the body in' producing the web portion 12 thereof. Y

It will be obvious that a connecting plug manufactured in accordancewith the hereinbefore described method results in a plug of thehereinbefore described type which is adequate to stand the wear, stressand strain to which plugs of this type are subjected, thus holding theirreplacement down to a minimum.

l/Vhat is claimed is:

1. rPhe steps in the methodr of manufactun ing electrical connectingplugs, which consists informing an a'pertured body with a web portionthereon, positioning a pin provided with an angular extension alongthe ii apei ture oi tne body by inserting it through the o iening formed inthe body in producing the web portion thereof with the extensiondisposed adjacent asurface of the body atone y end of the web portionthereof, positioning an apertured contact on the pin adjacent an outerend surface of the body, insulating the contact and the pin includingthe angular eX- tension thereof from the body, and then compressing t-hesevera-l parts ina direction parallel to the longitudinal axis of thebody and while under such compression rigidly uniting the contact to thepin.

2. rlhe steps in the method of manufacturing electrical connectingplugs, which consists in forming an apertured body with a web portionthereon, positioning a pin proi vided with an angular extension alongthe aperture of the body with the extension disposed adjacent a surfaceofthe body at one end of the web portion thereof, positioning anapertured Contactl on the pin, insulating i the Contact and the pinincluding the angular extension thereof from the body,A and then rigidlyuniting the several. parts by lodging l material of the contact in theperipheral surface of the pin while the several parts are undercompression in a direction parallel to the longitudinal axis of thebody.

3. A method of manufacturing electrical connectingplugs, whichconsists'in assem-.

bling a plurality of contacting members on an element having anindentation, positioning an end member over the identation, andswagingthe material thereof into the indentatioirto form a rigidmounting.`

4;. A method of. manufacturing electrical connecting plugs, whichconsists in assembling a plurality of contacting members on an element,insulating the contacting mem-V bers, compressing the contacting.members with an end meinberinserted on the element, and swaging the endmember to lock it' to the element. n j

5. A method of manufacturing electrical connecting plugs, whichconsistsin assembling a plurality of apertuiedcontacting ymembers on an elementprovided with peioo ripheral depressions, compressing the 'contactingmembers longitudinally of the element, and causing an end contactingmember to lill said depressions to form a rigid mounting.

In witness whereof, I hereunto subscribe my name this 15th dayofoJuly A.D., A1927.

BEN'KING noni).

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